1. Field of the Invention
The present invention relates generally to apparatus and methods for providing percutaneous access to internal body cavities and lumens for drainage, feeding, and other purposes. More particularly, the present invention relates to apparatus and methods for placing an elastic access tube within a percutaneous penetration to a target location within a patient's body.
Numerous catheterization procedures rely on initial formation of a percutaneous penetration through a patient's skin and subsequent insertion of a tubular catheter through the penetration into a body cavity or other target location. Catheterization is performed for a wide variety of purposes, including vascular access for performing diagnostic, interventional, and therapeutic procedures; drainage; feeding, and the like.
Of particular interest to the present invention, flexible catheters are frequently introduced to the kidneys, bladder, chest, lungs, gallbladder, and peritoneum, for drainage, and to the stomach, jejunum, duodenum, and large and small intestines for feeding. Such drainage and feeding catheters can be left in place for prolonged periods, frequently weeks or months, and may require periodic exchange as the catheters become blocked, dislodged, or otherwise ineffective.
Drainage and feeding procedures are frequently performed with a relatively simple elastomeric catheter referred to as a Foley catheter. The Foley catheter is an elastomeric tube having an inflatable balloon anchor near its distal end. The Foley catheter is typically introduced through a previously formed penetration so that the balloon lies within the body cavity of interest. The balloon is then inflated as an anchor, and drainage or feeding effected through a lumen of the catheter body. Foley catheters are widely used in percutaneous nephrostomies, bladder drainage procedures, jejunostomies, gastrostomies, and the like. In place of such expandable balloon structures, other conventional drainage and feeding catheters employ expandable Malecot structure at their distal ends.
For long-term placement, it is necessary that both feeding and drainage catheters be firmly anchored in place and sealed within the percutaneous penetration in order to lessen the risk of leakage, infection, and the like. It is also necessary, however, that the catheters be readily removable so that the catheters can be replaced when fouling occurs or for other reasons.
The ability to balance the requirements for firm anchoring and sealing within the percutaneous penetration with ease of replaceability has been particularly difficult in the case of feeding catheters used in gastrostomy procedures. The most common technique for placing feeding tubes is referred to as "percutaneous endoscopic gastrostomy," where an endoscope is introduced through the throat and into the stomach to locate a desired insertional location. Once the location is identified, a light on the endoscope allows the physician to use a needle to introduce a guidewire into the stomach. The guidewire is snared with a device introduced through the endoscope, and the guidewire is pulled out through the mouth. The guidewire is then used to pull a long, tapered gastrostomy tube inward through the mouth, to the stomach, and outward through the penetration. The taper provides an effective seal within the percutaneous penetration, and a permanently expanded "mushroom" on the tube prevents accidental withdrawal of the tube. While effective in many ways, such percutaneous endoscopic gastrostomy procedures suffer from certain disadvantages. The procedures can cause infections as the device must be drawn through the mouth and esophagus (where bacteria are prevalent) and into the freshly created wound site. The procedures require that the endoscope be introduced through the esophogus twice. Often, the second placement is very difficult because of damage caused during the first placement. More importantly, the permanently anchored feeding tube which is placed through such procedures is very difficult to remove and must be withdrawn through the patient's mouth, requiring yet another placement of the endoscope.
Improvements on the Foley catheter have been proposed by Dr. Constantin Cope, where a Foley catheter may be stiffened and thinned prior to introducing through a previously formed tissue penetration. Stiffening is achieved using an internal introducer rod which engages a distal end of the catheter and elongates the tube by a small amount. Such improved Foley catheters have been proposed for use in nephrostomy and urinary diversion procedures. While such improved Foley catheters are easier to introduce through previously formed tissue penetrations, they do not generally result in dilation of the tissue tract (thus limiting their ability to provide an enlarged access lumen) and they cannot be introduced in a single step procedure.
For these reasons, it would be desirable to provide improved access tubes, systems, and methods useful in a wide variety of patient catheterization procedures, including gastrostomy, nephrostomy, jejunostomy, urinary diversion, and the like. Such tubes, systems, and methods should allow for easy placement and removal of the access tube, while at the same time resulting in firm anchoring and sealing of the access tube within a percutaneous penetration. It would also be desirable to provide access tubes which are capable of direct introduction, i.e., are self-introducing, or which would be capable of introduction in combination with separate dilation or other percutaneous introduction procedures. Preferably, the access tubes will be self-sealing and/or self-anchoring within the percutaneous penetration, preferably being radially expandable within the penetrations to provide self-anchoring and relatively large access lumens.
2. Description of the Background Art
Use of an internal rod for elongating and stiffening a Foley catheter for introduction through a fresh or established nephrostomy tract is described in Cope (1981) Urology 27:606. See also, Cope et al. Atlas of Interventional Radiology, Lippencott, 1990, pages 11.5-11.6. Percutaneous embolectomy using a sheath having a self-expanding distal end which is maintained in a reduced diameter configuration by applying axial tension with an internal stylet is described in Vorwerk et al. (1992) Radiology 187:415-418; Weigele et al. (1992) Radiology (1992) 185:604-606; and European Patent Application 385 920. A drain for the eardrum which is inserted using a sharpened internal stylet is described in U.S. Pat. No. 3,948,271. U.S. Pat. No. 5,102,401, describes a catheter formed from a hydrophilic material which expands when exposed to a wet environment. A radially expanding dilator is described in U.S. Pat. No. 5,183,464. A radially expanding endotracheal tube is described in U.S. Pat. No. 4,141,364. Other percutaneously introduced tubes and sheaths are described in U.S. Pat. Nos. 5,183,471; 5,176,649; 5,074,867; 4,871,358; 4,589,868; 4,112,932; and 4,077,412.